#9709: TFW IOBOUND
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Reporter: spamme@… | Owner: danielk
Type: Bug Report - General | Status: new
Priority: minor | Milestone: unknown
Component: MythTV - Recording | Version: Trunk Head
Severity: medium | Keywords:
Ticket locked: 0 |
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I keep getting these messages at the start of recordings. Between 1 and 5
(sometimes more) occurences at the beginning of every recording.
TFW IOBOUND 5169 free(0) size (4194304) cnr(1)
Normally, I assume that this message means your hard drive isn't good
enough. However, this is NOT the case.
The OS and mysql are on 1 hard drive and recordings on another.
I have a RAID 6 array with hardware controller, 4GB of RAM, and a AMD
Quad Core 3Ghz processor dedicated to mythtv and general file storage.
Assuming that 4194304 is a size in bytes, that is so small that it is
useless, 4MB of buffer???? How do I increase this tiny number. Since
even the most humble hard drives should be able to push 40mb/s I would
like a 40mb buffer. Either that or a buffer that automatically expands
and contracts as needed.
I am especially concern because I have 4 HD tuners if 4MB isn't enough
for 1 HDTV stream it certainly can't handle 4 at once.
My lowest RAID 6 speed is 100mb/s write and 500mb/s read. Typically
write speeds are 200mb/s and read speed can reach 650mb/s.
I found a "HD ringbuffer size" setting in mythtv-setup->General and I
slowly cranked it up to its max of 96,256kb of ram to no effect.
I have tons of system resources including TB of free space on the RAID
and etc. This message should not be happening to me. Mythtv could use
500mb of ram as a buffer and I wouldn't care, but getting IOBOUND on my
system must indicate an inefficiency in the code.
A HD recording is about 2-4mb/s each, and with modern hardware we should
never be IOBOUND. Ten concurrent recording should max at about 40mb/s a
number well within any modern hard drives capabilities.
I have extensively benchmarked all hardware and have upgraded to newer
and faster equipment. I am still getting TFW IOBOUND...... My hardware
is WAY above what I should *need*.
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Ticket URL: <http://code.mythtv.org/trac/ticket/9709>
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